Flash memory is in the process of becoming a leading storage device due to the declining bit-cost of flash memory in recent years. The technology described in Patent Literature 1 discloses an alternative HDD (hard disk drive) device using flash memory, being one of a nonvolatile memory.
More specifically, the alternative device of Patent Literature 1 comprises a two-value flash memory, which comprises a memory cell capable of storing two bits in one memory cell, and a volatile memory. The volatile memory functions as a cache memory for the two-value flash memory. At power shutdown, the alternative device saves the storage contents of the volatile memory to the multilevel flash memory. By writing only one bit of data to one memory cell at this time, the alternative device reduces the amount of power consumed during the write.